Leakage preventing structure of dish washer

ABSTRACT

A leakage preventing structure of a dishwasher is provided. The structure includes a wash motor with a motor shaft disposed at its center, a sump housing that the motor shaft passes through, and a sealing portion that seals the space between the wash motor and the sump housing. The sealing portion is an aircap that controls the water level of washing water introduced into the aircap by means of air pressure of air inside the aircap, or a sealing member coupled to the motor shaft of the wash motor.

This application claims the benefit of Korean Patent Application No.2004-0047447, filed on Jun. 24, 2004; Korean Patent Application No.2004-0047446, filed Jun. 24, 2004 and PCT Application No.PCT/KR2005/001690, filed on Jun. 7, 2005, which are hereby incorporatedby reference for all purposes as if fully set forth herein.

TECHNICAL FIELD

The present invention relates to a dishwasher, and more particularly, toa leakage preventing structure of a dishwasher, which can preventwashing water stored in a sump from leaking out through a through-holefor a motor shaft.

BACKGROUND ART

A dishwasher is one of home appliances that can remove food particlesfrom dishes using high-pressure washing water sprayed from nozzles.

To be specific, a dishwasher includes a tub forming an interior space inwhich dishes to be washed are placed, a sump mounted under the tub tostore washing water, a wash pump attached to one side of the sump topump the washing water contained in the sump to spraying nozzles, a washmotor for driving the wash pump, a drain pump for draining dirty washingwater after the washing has been completed, and a drain motor fordriving the drain pump.

The wash pump is installed inside the sump and the wash motor isinstalled below the sump, so that the wash motor and the wash pump areperpendicularly coplanar. Specifically, the shaft of the wash motor inthe above configuration passes through into the sump and is coupleddirectly to the pump. An impeller inside the pump rotates according tothe rotation of the motor shaft, thereby pumping washing water.

Here, when the motor shaft is inserted through the bottom of the sump,washing water runs down the outer surface of motor shaft during itsrotation and leaks out from the sump.

While the motor shaft rotates, friction created between the shaft andthe sump wears and reduces the effectiveness of the sealing functionbetween the motor shaft and the sump. When a gap is created in the motorshaft through-hole between the motor shaft and the sump, washing watercan leak through the gap.

Also, when the fixture of a sealing member to the sump precludes theinstallation of the motor, the surface of the sealing member can bedamaged in the installation process and washing water can leak out.

DISCLOSURE OF INVENTION

Technical Problem

An object of the present invention is to provide a leakage preventingstructure of a dishwasher capable of preventing washing water stored inthe sump from leaking out along an outer surface of a motor shaft.

Another object of the present invention is to provide a leakagepreventing structure of a dishwasher with an improved seal assemblymethod and process that can prevent incurring damage to the sealingmember during its assembly.

Technical Solution

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, aleakage preventing structure of a dishwasher according to the presentinvention includes: a wash motor with a motor shaft at its center; asump housing allowing insertion therethrough of the motor shaft; and asealing portion for sealing the gap between the wash motor and the sumphousing.

The sealing portion may be an aircap for controlling the water level ofwashing water that enters the aircap, via air pressure therein, or asealing member coupled to the wash motor shaft.

Advantageous Effects

The leakage preventing structure of a dishwasher according to thepresent invention prevents washing water from leaking out along anoutside of a motor shaft.

More specifically, a sealing cover installed in a sealing case of themotor shaft and a sealing oil primarily prevents a washing water fromleaking out, and an aircap covering the sealing cover secondarilyprevents washing water from leaking out toward the sealing cover.

Additionally, after a sealing member for preventing washing waterleakage is coupled to the motor shaft, the motor is installed on thesump, so that no damage is incurred to the sealing member duringinstallation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of a dishwasher with a leakagepreventing structure according to the present invention;

FIG. 2 is an exploded perspective view of a sump having a leakagepreventing structure according to a first embodiment of the presentinvention;

FIG. 3 is a vertical, sectional view of a sump having the leakagepreventing structure according to the first embodiment of the presentinvention;

FIG. 4 is a cut-away perspective view of the leakage preventingstructure according to the first embodiment of the present invention;

FIG. 5 is an enlarged sectional view showing an aircap that is partiallyimmersed in washing water according to the first embodiment of thepresent invention;

FIG. 6 is a perspective view of a wash motor according to a secondembodiment of the present invention; and

FIG. 7 is a sectional view of the wash motor of FIG. 6 coupled to a sumphousing.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of a leakage preventing structure ofa dishwasher according to the present invention will be described indetail with reference to the accompanying drawings. While the presentinvention has been described and illustrated herein with reference tothe preferred embodiments thereof, it will be apparent to those skilledin the art that various modifications and variations can be made thereinwithout departing from the spirit and scope of the invention. Thus, itis intended that the present invention covers the modifications andvariations of this invention that come within the scope of the appendedclaims and their equivalents.

FIG. 1 is a schematic sectional view of a dishwasher with a leakagepreventing structure according to the present invention.

Referring to FIG. 1, the dishwasher 100 having the leakage preventingstructure of the present invention includes a tub 110 forming the outershape of the dishwasher 100 and having a dish washing chamber on itsinside, a door 111 formed on the front of the tub 110 to open and closethe dish washing chamber, and a sump 200 formed at the central bottomportion of the tub 110 for holding washing water.

Moreover, the dishwasher 100 includes a water guide 140 for guidingwashing water pumped by a wash pump, a lower nozzle 160 disposed on topof the sump 200 and formed at the bottom of the dish washing chamber forspraying washing water upward, an upper nozzle 150 attached to the upperportion of the water guide 140 and formed to extend perpendicularly fromthe water guide 140 to the center of the dish washing chamber, and a topnozzle 155 formed on the ceiling portion of the tub 110 for sprayingwashing water perpendicularly downward.

In order to wash dishes through the upper nozzle 150, an upper rack 120is installed above the upper nozzle 150. In order to wash dishes throughthe lower nozzle 160, a lower rack 130 is installed above the lowernozzle 160.

The upper rack 120 is supported by rails (not shown) on the inner sidesof the tub 110 and slides forward and backward.

An operation of the dishwasher 100 according to the present inventionwill be described below.

First, a user opens the door 111 of the dishwasher 100, and pulls theupper rack 120 and/or the lower rack 130 out from the dish washingchamber. Next, the user places dishes on the upper and/or lower racks120 and/or 130, closes the door 111. When the user presses the powerbutton. the dish washing cycle begins.

When power is supplied to the dishwasher 100 and a wash cycle begins,washing water enters the sump 200. When the sump 200 is filled withwashing water, the wash motor 330 operates. When an impeller inside awash pump (not shown) connected to the shaft of the wash motor spins,washing water is pumped to the lower nozzle 160 and the water guide 140.

The washing water pumped to the water guide 140 moves to the top andupper nozzles 155 and 150 from where it is sprayed into the dish washingchamber. The dishes stacked on the upper and lower racks 120 and 130 arewashed by the sprayed washing water.

Here, the top nozzle 155 sprays washing water downward and the uppernozzle 150 sprays washing water upward to wash dishes stacked on theupper rack 120.

The lower nozzle 160 sprays washing water upward to wash dishes stackedon the lower rack 130. Nozzle openings may be formed on the lowerportion of the upper nozzle 150 to spray washing water downward as wellas upward, in order to simultaneously wash the upper portions of dishesstacked on the lower rack 130.

When the wash cycle is completed, a drain pump (not shown) pumps thedirty washing water in the sump 200 out from the dishwasher 100.

When the dirty washing water is expelled to the outside, clean washingwater enters the sump 200 via an intake opening, and is then sprayed inthe same manner through the nozzles 150, 155 and 160 as in the washcycle. Hence, the clean washing water sprays and rinses the dishes.

After the rinse cycle, a dry cycle is carried out. In this manner, thedish washing process is completed.

FIG. 2 is an exploded perspective view of a sump having a leakagepreventing structure according to a first embodiment of the presentinvention.

Referring to FIG. 2, the sump 200 of the dishwasher with the leakagepreventing structure according to the present invention includes a-sumphousing 290 for storing water drawn through a washing water supply pipe,a wash motor 330 installed below the sump-housing 290, and a disposer280 connected to the motor shaft 331 protruding from the center of thewash motor 330, for rotating and miniaturizing food particles.

The sump 200 further includes a pump case 256 installed at the top ofthe disposer 280 for pumping washing water stored inside the sumphousing 290, and an impeller 250 inside the pump case 256 for pumpingwashing water. The impeller 250 has the motor shaft 331 inserted in acentral portion thereof, and rotates to pump washing water according tothe rotation of the motor shaft 331.

Furthermore, a mesh filter 270 is installed between the disposer 280 andthe pump case 256 and filters food particles, which have beenminiaturized by the disposer 280 but are still too large, from enteringthe pump case 256.

A soil chamber 230 covers the top of the pump case 256 and forms apumping channel that guides the flow of washing water pumped in the pumpcase 256.

In addition, a filter 220 rests on top of the soil chamber 230 and has aspray nozzle connecting port at an edge of its central portion. Thespray nozzle connecting port is connected to the spray nozzles so thatwashing water pumped along the pumping channel formed by the soilchamber 230 is guided to each spray nozzle. Also, a distribution valve260 is installed on a side of the soil chamber 230 in order toselectively guide the washing water pumped along the pumping channel toeach spray nozzle.

More specifically, a washing water through-hole 221 and a mesh filter227 are formed at an edge of the filter 220 for filtering food particleswashed from dishes in a preliminary filtering stage. An insert hole 223is formed at the center of the filter 220 for installing a lower nozzlearm holder 210 thereon, to be coupled to the lower nozzle. Also, a waterguide insertion sleeve 226 is formed at a predetermined height anddiameter on an edge of the filter 220 for inserting the lower end of thewater guide 140 therein. The water guide 140 is a

-shaped pipe for guiding washing water pumped by the wash pump 256 fromthe bottom of the tub to the upper nozzle toward the top of the tub.

A distribution valve housing 235 is formed on a portion of the soilchamber 230 to receive the distribution valve 260. A lower nozzle feed236 is formed on the top of the soil chamber 230. The lower nozzle feed236 is bent from the distribution valve housing 235. Also, a water guidefeed 237 is formed to guide washing water from the distribution valvehousing 235 towards the water guide insertion sleeve 226.

At the periphery of the soil chamber 230, a drain channel 241 is formedto have a predetermined width and depth and constructed in accordancewith the soil chamber 230 structure. A turbidity sensor receptacle 232for receiving a turbidity sensor is formed on one side of the drainchannel 241, and a drain hole 242 connected to the drain pump and thelower end of the sump is formed at the bottom of the other side. Here,the turbidity sensor is a sensor installed on one side of the sump forsensing impurities in washing water during a dish washing cycle.

Further, a turbidity sensor guide channel 233 guides washing waterpumped in the pump case 256 to the turbidity sensor inserted in theturbidity sensor receptacle 232.

The washing water that descends through the washing water through-hole221 on the filter 220 is collected in the sump housing 290. The washingwater that descends onto the mesh filter 227 has its particlecontaminants filtered by the mesh filter 227, then proceeds along thedrain channel 241 disposed below the mesh filter 227, and is collectedby the sump housing 290.

At a central portion of the pump case 256 is an impeller insertionrecess 257 for installing an impeller 250 therein. A pumping channel 258is formed by the outer circumference of the impeller insertion recess257 and the outer portion of the pump case 256. The pumping channel 258has a predetermined depth determined by the outer wall of the pump case256. Washing water that enters the pump case 256 moves along the pumpingchannel 258 towards the distribution valve 260.

The sump housing 290 includes a water supply port 291 formed on a lowerside thereof, a drain pump case 296 recessively formed roughly oppositeto the water supply port 291, and a heater receptacle 292 recessed apredetermined depth at the center of the sump housing 290.

More specifically, at the center of the heater receptacle 292 a motorshaft through-hole 293 is formed for a motor shaft to pass therethrough,and at one side of the sump housing 290 a heater insertion slot 298 isformed for a heater 320 to be inserted therethrough. A cylindricalsealing case 400, which has a diameter larger than the motor shaftthrough-hole 293 and a predetermined height, is formed above the motorshaft through-hole 293. Inside the sealing case 400, a sealing cover(which will be described later) is inserted around the motor shaft 331to prevent leakage in a preliminary stage. Furthermore, an aircap 500 isinserted on the outer surface of the motor shaft 331 between the lowerend of the pump case 256 and the upper end of the sealing case 400 so asto prevent leakage in a secondary stage. A detailed description of theaircap 500 will be made later.

The drain pump case 296 is connected to the soil chamber drain groove297, and the drain motor 300 is installed on the drain pump case 296.The drain impeller 310, which spins inside the drain pump case 296 topump washing water out through a drain hose, is attached to the front ofthe drain motor 300.

The sump housing 290 has a distribution valve mount 295 formed on asurface outside of the heater receptacle 292, with a turbidity sensormount 294 formed a pre-determined distance apart from the distributionvalve mount 295.

To briefly describe the flow of washing water in the above-describedsump structure according to the present invention, the washing waterstored in the lower portion of the sump is first suctioned through therotation of the wash motor 330 towards the impeller 250 installed in thepump case 256. Next, the washing water pumped by the rotation of theimpeller 250 flows through the mesh filter 270 and is filtered in apreliminary stage. Subsequently, the washing water flows along thepumping channel 258 formed by the pump case 256 and the soil chamber230, and respectively flows to the upper and lower nozzles (not shown).Here, the washing water is divided by the distribution valve 260, andrespectively flows to the lower and upper nozzles through the lowernozzle feed 236 and water guide feed 237.

More specifically, the distribution valve 260 opens the washing waterpassage to only one of the upper and lower nozzles 150 and 160 at agiven time. After the given time elapses, the passage to the othernozzle is opened, so that washing water is evenly sprayed from the upperand lower nozzles.

A portion of the washing water that flows through the passages passesthe turbidity sensor (not shown) and flows along the drain channel 241formed on the outer portion of the soil chamber 230 to collect at thebottom of the sump. During the draining process, the washing water movesthrough the drain pump case 296 and is drained through the rotatingdrain impeller 310 when the drain motor 300 operates.

FIG. 3 is a vertical sectional view of a sump having the leakagepreventing structure according to the first embodiment of the presentinvention, and FIG. 4 is a cut-away perspective view of the leakagepreventing structure according to the first embodiment of the presentinvention.

Referring to FIG. 3, the leakage preventing structure according to thepresent invention that is the aircap 500 is inserted, as previouslydescribed, around the motor shaft between the bottom of the pump case256 and the sealing cover 410.

The aircap 500 may be installed at the bottom of the disposer 280.Furthermore, the aircap 500 may have a diameter large enough toaccommodate the outside of the sealing case 400 therein. The sealingcase 400 is a cylinder having a predetermined diameter and height, andhas the motor shaft through-hole 293 disposed at its center forinserting the motor shaft 331 therethrough.

A sealing cover 410 is placed inside the sealing case 400. Sealing oil420 is filled in the space created by the sealing case 400 and thesealing cover 410. Specifically, in order to maintain a sealed state inthe space between the sealing cover 410 and the outer surface of themotor shaft 331, a plurality of sealing lips 411 are formed.Accordingly, the sealing lips 411 are pressed firmly against the outsideof the motor shaft 331, to prevent washing water from leaking into thesealing case 400. Because sealing oil 420 seals the space formed by thesealing cover 410 and the sealing case 400, if washing water and thesealing oil 420 should meet, they do not mix. Furthermore, the sealingoil 420 also acts as a lubricant for the motor shaft 331.

Referring to FIG. 4, the leakage preventing structure according to thepresent invention, that is, the aircap 500 includes a circular aircapupper plate 520 having a predetermined radial width, and a motor shaftthrough-sleeve 510 extending upward from the center of the aircap upperplate 520 and having a predetermined diameter and height foraccommodating insertion of the motor shaft 331 therethrough.

From the bottom of the outer circumference of the aircap upper plate 520is a cylindrical aircap outer wall 530 that extends a predetermineddistance downward, and an aircap inner wall 540 having a diametersmaller than the outer wall 530 is also formed at the bottom of theaircap upper plate 520. An outer chamber 560 formed between the aircapinner and outer walls 540 and 530 and an inner chamber 560 enclosed bythe aircap inner wall 540 contain a predetermined amount of air.Accordingly, the air pressure inside the inner and outer chambers 560and 550 prevents the water level of washing water from rising beyond acertain point within the chambers. In other words, the water level ofthe washing water storage portion in the sump is different from that inthe two chambers 550 and 560.

Here, the number of inner walls 540 of the aircap is not limited to thenumber in an embodiment of the present invention, and multiple chambersmay be created by forming multiple inner walls.

FIG. 5 is an enlarged sectional view showing an aircap that is partiallyimmersed in washing water according to the first embodiment of thepresent invention.

Referring to FIG. 5, the aircap 500 according to the present inventionis installed on top of the sealing case 400 and covers the sealing case400. The sealing case 400 is completely covered by the inside of theinner wall 540 of the aircap 500. The ends of the aircap's outer andinner walls 530 and 540 are spaced slightly apart from the floor of thesump housing 290. Washing water is allowed to flow through this slightgap.

When washing water enters into the sump housing 290, washing waterslowly enters the chambers 550 and 560, where its water level graduallyrises. As previously described, the air present inside the chambers 550and 560 becomes pressurized as the water level of the washing waterrises. The water level rises until the pressure of the washing waterbecomes equal to that of the air. The maximum water level (M) allowed inthe chambers 550 and 560 may be set to be lower than the height ofsealing case 400.

By setting the water level (H) of the washing water that enters theaircap 500 to be less than the height of the sealing case 400, washingwater is prevented from leaking between the sealing case 400 and thesealing cover 410.

Mode for the Invention

FIG. 6 is a perspective view of a wash motor according to a secondembodiment of the present invention, and FIG. 7 is a sectional view ofthe wash motor of FIG. 6 coupled to a sump housing.

Referring to FIGS. 6 and 7, the wash motor 330 having the leakagepreventing structure of the present invention includes a motor housing332 for protecting a stationary member and a rotating member, a bearingportion 334 protruding a pre-determined distance upward from the centerof the motor housing 332 and having a bearing within, a motor shaft 331running through the top of the bearing portion to extend substantiallytherebeyond, and a sealing member 600 coupled to the motor shaft 331 torest on top of the bearing portion 334. The sealing member 600 istightly adhered to the inside of the sealing case 400, so that washingwater cannot leak between the sealing case 400 and the sealing member600. The sealing member 600 may be made of a rubber material having apredetermined elasticity.

After the sealing member 600 is coupled to the motor shaft 331, it isinserted into the sealing case 400 formed at the bottom of the sumphousing 290. The above method for inserting the sealing member 600before the motor is installed is much less likely to damage the surfaceof the sealing member than a method where the sealing member is firstinstalled inside the bottom of the sump housing 290, after which themotor shaft is inserted through the sealing member.

As shown in FIG. 7, the sealing member 600 is installed on the outerbottom portion of the sump housing 290, instead of inside the sumphousing 290, thereby facilitating replacement of the sealing member 600.In other words, when the sealing member 600 becomes substantially worn,the wash motor 600 is disassembled from the sump housing 290. Then theworn sealing member 600 is pulled off the motor shaft 331, and replacedwith a new one.

INDUSTRIAL APPLICABILITY

The leakage preventing structure of a dishwasher according to thepresent invention prevents leakage in the dishwasher sump and thereforehas a high industrial applicability.

1. A dishwasher, comprising: a tub for accommodating dishes for washing;a sump housing receiving water for dishwashing, the sump housing coupledto the bottom of the tub; a wash motor mounted to the outer bottomsurface of the sump housing and having a motor shaft extended into thesump housing by passing through the bottom surface of the sump housingfrom the wash motor; a wash pump located within the sump housing, thewash pump including: a pump case; and an impeller for pumping the waterfor dishwashing within the pump case, wherein the impeller is connectedto an end of the motor shaft; a sealing case upwardly extended from aninner bottom surface of the sump housing; a sealing cover fitted withinthe sealing case and penetrated by the motor shaft; and an air capcovering the sealing case and the sealing cover and penetrated by themotor shaft, wherein the air cap has a space therein for accommodatingair, in order to prevent the water for dishwashing from being drawn intothe sealing case, and the air cap includes: an upper plate; a motorshaft through-sleeve extending upward by a predetermined diameter andheight from the upper plate, the motor shaft through surrounding themotor shaft to be in close contact with the outer surface of the motorshaft; an outer wall extending downward from an edge of the upper plate;and an inner wall extending down ward from the bottom surface of theupper plate, wherein the inner wall is defined within the outer wall bybeing a predetermined distance away from the outer wall such that a voidspace is formed between the inner wall and the outer wall.
 2. Thedishwasher according to claim 1, wherein end portions of the outer walland the inner wall are respectively a predetermined distance away fromthe inner bottom surface of the sump housing such that air and the waterfor washing dishes are drawn into the air cap.
 3. The dishwasheraccording to claim 1, wherein the sealing case is configured to bereceived in the space defined by the inner wall of the air cap.
 4. Thedishwasher according to claim 1, wherein the sealing cover is bentdownward to be in close contact with the inner bottom of the sumphousing, and has a space therein to receive sealing oil.
 5. Thedishwasher according to claim 4, wherein an inner circumference of thesealing cover, which is in contact with the motor shaft, has a pluralityof sealing lips which are firmly pressed to the outer surface of themotor shaft, in order to block off the water for washing into thesealing cover.